Automatic registration system for use with position tracking an imaging system for use in medical applications

Abstract

A method of automatic registration includes forming an image of a body part including a representation of markers fixed in a known position in space relative to a reference mount, positioning a sensing unit in a known position in space relative to the reference mount, and automatically registering the sensing unit in space relative to the formed image based on the location of the markers in the formed image, the known location of the markers relative to the reference mount, and the known location of the sensing unit relative to the reference mount.

We claim:  
     
       1. A method of automatic registration, comprising the steps of: 
       forming an image of a body part including a representation of markers fixed in a known position in space relative to a reference mount having an electromagnetic field generator in a known position in space relative to the reference mount;  
       positioning an electromagnetic field sensing unit in a known position in space relative to the reference mount, and  
       automatically registering the electromagnetic field sensing unit in space relative to the formed image based on the location of the markers in the formed image, the known location to the markers relative to the reference mount, and the known location of the electromagnetic field sensing unit relative to the reference mount.  
     
     
       2. The method of  claim 1  further comprising providing the reference mount comprising a headset. 
     
     
       3. The method of  claim 1  wherein the step of providing includes providing the headset including a frame having a nose mount, and first and second ear mounts. 
     
     
       4. The method of  claim 2  further including placing the headset on a patient's head in a repeatable fashion. 
     
     
       5. The method of  claim 1  wherein the markers are fixed non-invasively. 
     
     
       6. The method of  claim 1  wherein the electromagnetic field sensing unit is positioned non-invasively. 
     
     
       7. The method of  claim 1  wherein said forming step comprises attaching the electromagnetic field generator to the reference mount. 
     
     
       8. The method of  claim 1  wherein said positioning an electromagnetic field sensing unit step comprises positioning a plurality of electromagnetic field sensing units in space relative to the formed image based on the location of the markers in the formed image. 
     
     
       9. The method of  claim 8  further comprising positioning at least one of said plurality of electromagnetic field sensing units on a medical instrument. 
     
     
       10. The method of  claim 1 , further comprising providing the reference mount with a transmitter in a known spatial relationship to at least one fiducial ball, and automatically generating a mapping function to translate a transmitter coordinate system to an image coordinate system. 
     
     
       11. The method of  claim 1 , further comprising generating a mapping function based on the relative orientation of the electromagnetic field generator with respect to the reference mount.